<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8"/>
        <meta name="viewport" content="width=device-width, initial-scale=1.0"/>
        <meta http-equiv="X-UA-Compatible" content="ie=edge"/>
        <title>Document</title>
        <script>
            /* 
                charCodeAt()
                    格式：字符串.charCodeAt(下标)
                    功能：访问字符串中对应下标字符的ASCII码值。


                String.fromCharCode();
                    格式：String.fromCharCode(码值1, 码值2...);
                    功能：将传入的ASCII码值转成对应的字符
                    返回值：组成的字符串
             */
             /* var str = "hello";
             alert(str.charCodeAt(1)); */

             var str = String.fromCharCode(97, 98, 99, 100);
             alert(str);
        </script>
    </head>
    <body>
        
    </body>
</html>